Piston and piston ring



Patented @ct. l6, i934 I IPHS'EQN AND lPlIS'E'UN RING Wesley lE. McCullough, lfiiagerstown, 11nd assignor to The Perfect @ircle Company, lillagcrstown,

limit, a corporation of Indiana Application May 5, 1932, Serial No. 609,383

4 Claims.

My invention relates to pistons and piston rings for internal combustion engines and it has to do particularly with slotted rings for conveying excess lubricant from the cylinder wall and preventing oil pumping.

The principal object of my invention is to provide an improved ring with circumferentiallyelongated, spaced slots and adapted to exert a more nearly uniform pressure throughout its circumference against the cylinder wall thereby increasing the efliciency and life of the ring.

A further and more specific object is to provide a ring of the foregoing character having a plurality of slots separated by bridge portions reducecl in cross-sectional area and weakened by openings extending ther'ethrough, whereby the bending action, and consequently the ring pressure, is more nearly uniform throughout the circumference of the ring.

Other objects and advantages will become apparent as this description progresses and by reference to the drawing wherein,---.

Fig. 1 illustrates one form of oil ring embodying my invention applied toa piston of an internal combustion engine, the fragments of the parts being shown in longitudinal cross section;

Fig. 2 is a plan view, partially in section, of the another form of ring embodying my invention;

with a bottom groove 12 having drain apertures 13 extending to the interior of the piston so that excess lubricant scraped from the cylinder wall by my improved ring 14. may be returned to the crank case. The ring 14 is split in the ordinary manner as at 15 and is provided in its outer face with a continuous groove 16 which communicates with the piston groove 12 through a plurality of reduced-width, circumferentially-elongated and equally spaced slots 1'7. These slots have converging ends 17"- forming the sides of triangularshaped bridges 18.between the ends of and adjoining adjacent slots. The ring, unless provided otherwise, has a greater section at the bridges 18 and I have found that, in certain instances, due to the lack of uniformity in the cross-sectional area of the ring, there may be a tendency for the ring not to maintain its true circular form when compressed to the working diameter of the cylinder with the resultthat the ring does not exert a uniform pressure throughout its circumference against the cylinder wall, and the lack of uni-' formity may be sufficiently pronounced to affect the preferred performance of the ring. f

My invention tends to reduce to a minimum the tendency toward the foregoing condition. More particularly, my invention contemplates the reduction of the section of the ring at'the bridges 18 thereby weakening the same at those points and tending to more nearly uniformize the bending action and the pressure of the ring throughout its entire circumference. Specifically, I provide each of the bridges 18 with an opening 19 extending entirely therethrough, and, preferably, of a width substantially equal to the width of the slots 17. The diameter of the openings 19,. however, may be increased or diminished, as desired, to the end that the desired uniformity of action and flexibilty of the ring throughout its circumference may be accomplished.

In Figs. 4 and 5 I have shown another form of slotted ring embodying my invention. This ring is split in the ordinary manner as at 20 and is provided with a plurality of circumferentiallyelongated, equally-spaced slots 21 which extend from the outer to the inner face of the ring.

.These slots, like the slots of the form of Fig. 2

have converging ends 21 constituting the sides of triangularly shaped bridges 22 which have a Wide base 22 at the inner face of the ring and a comparatively small outer portion 22 terminating in, and flushwith, the outer face of the ring.

Each of the bridges 22 is provided with an open will be appreciated from the foregoing. In both wear, and the life of the ring and the associated operating parts is greatly increased.

It will be understood that while I have shown and described only two forms of my invention, other changes in details and arrangements of parts may be made without departing from the spirit and scope of my invention as defined by the claims which follow.

I claim:

1. A piston ring of the class described having a body with a plurality of circumferentially-elongated, spaced slots therein, the surfaces between said slots being provided with openings of substantially the width of said slots extending radially entirely through such surfaces to reduce the cross-sectional area of the ring at those points to more nearly that at said slots.

2. A piston ring of the class described which comprises a body having a plurality of spaced elongated slots therein and extending therethrough from its outer to its inner face, the surfaces between said slots having a relatively small and full body width surfiace terminating in said outer face and a larger and full body width surface terminating in said inner face, and having openings passing entirely therethrough of a diameter approximating the width of said slots.

3. In combination with a piston'for an internal combustion engine, having a piston ring groove with apertures extending from the back of the groove to the interior of the piston to permit the draining of oil to the crank case, of a piston ring -mounted in the groove and'having closely adjacent circumferentially-elongated slots extending therethrough to said groove, said slots being defined by bridge members having circular openings extending in radial direction entirely therethrough, which openings are of a width substantially equal to the width of said slots so as to weaken the ring at said bridge members and tending to uniformize the pressure of said ring throughout the circumference.

4. A piston ring of the class described which comprises a ring body having a plurality of elongated circumferential slots therein which extend in radial direction from the outer to the inner face of said body, adjacent ends of said slots being separated by triangularly-shaped body bridge portions, said bridge portions having openings extending radially and entirely therethrough and of sufiicient size to weaken the ring at said bridge portions and tend to uniformize the pressure of the ring throughout its circumference.

WESLEY E. McCULLOUGH. 

